1. Field of the Invention
The invention relates generally to a device for demarcating an area, in particular for limiting the freedom of movement of animals walking about freely.
2. Description of the Related Art
Devices are known for demarcating areas, in which a demarcating element is connected between a first vehicle and at least a second vehicle. At least the first vehicle is provided with a tracking arm structure for making it possible to track a guide element disposed in the area, such as for example a wire fencing. A device of this type is known from German Offenlegungsschrift DE 42 15 714. The known device comprises two tracked vehicles that are each provided with a tracking arm structure between which two wires are stretched for demarcating an area. The tracking arm structures each comprise a hook that can be hooked on a fencing. This known device has the disadvantage that the stretched wires between the two vehicles are directly connected with the tracking arm structures, which results in great forces being exerted on the tracking arm structures when relatively long wires are stretched between the vehicles. Also the forces exerted by the tracking arm structures on the wire fencings by means of the hooks can lead to the wire fencing breaking in those cases where excess loads are exerted upon it.
A further device is known from U.S. Pat. No. 6,062,165 which discloses a farming system comprising a circular plot of land. Electric fences defining a wedge shaped paddock may be moved around the plot. In one embodiment a vehicle supporting an end of one electric fence follows a circular perimeter fence around the plot. The vehicle comprises a tension device for applying tension to the electric fence and also a probe for following the perimeter fence. The probe is mounted on a pivotal arm, which is biased against the fence by a spring mounted on the vehicle. Pivoting of the arm steers the vehicle via a steering arm and tie rod mechanism. As mentioned above, such lateral biasing forces acting on a guide wire have been found generally undesirable, requiring more substantial structures to support the guide wire.